Getting help

Bug reports should be posted on
GitHub (and be sure
to read the bug reporting guidance below).

Installation

Add poltergeist to your Gemfile, and in your test setup add:

require'capybara/poltergeist'Capybara.javascript_driver=:poltergeist

If you were previously using the :rack_test driver, be aware that
your app will now run in a separate thread and this can have
consequences for transactional tests. See the Capybara README for more
detail.

Installing PhantomJS

You need at least PhantomJS 1.8.1. There are no other external
dependencies (you don't need Qt, or a running X server, etc.)

Running on a CI

Depending on your tests, one thing that you may need is some fonts. If
you're getting errors on a CI that don't occur during development then
try taking some screenshots - it may well be missing fonts throwing
things off kilter. Your distro will have various font packages available
to install.

What's supported?

Poltergeist supports all the mandatory features for a Capybara driver,
and the following optional features:

page.evaluate_script and page.execute_script

page.within_frame

page.status_code

page.response_headers

page.save_screenshot

page.driver.render_base64(format, options)

page.driver.scroll_to(left, top)

page.driver.basic_authorize(user, password)

element.native.send_keys(*keys)

window API

cookie handling

drag-and-drop

There are some additional features:

Taking screenshots with some extensions

You can grab screenshots of the page at any point by calling
save_screenshot('/path/to/file.png') (this works the same way as the PhantomJS
render feature, so you can specify other extensions like .pdf, .gif, etc.)
Just in case you render pdf it's might be worth to set driver.paper_size= with
settings provided by PhantomJS in here

By default, only the viewport will be rendered (the part of the page that is in
view). To render the entire page, use save_screenshot('/path/to/file.png',
:full => true).

You also have an ability to render selected element. Pass option selector with
any valid element selector to make a screenshot bounded by that element
save_screenshot('/path/to/file.png', :selector => '#id').

If you need for some reasons base64 encoded screenshot you can simply call
render_base64 that will return you encoded image. Additional options are the
same as for save_screenshot except the first argument which is format (:png by
default, acceptable :png, :gif, :jpeg).

Clicking precise coordinates

Sometimes its desirable to click a very specific area of the screen. You can accomplish this with
page.driver.click(x, y), where x and y are the screen coordinates.

Remote debugging (experimental)

If you use the :inspector => true option (see below), remote debugging
will be enabled.

When this option is enabled, you can insert page.driver.debug into
your tests to pause the test and launch a browser which gives you the
WebKit inspector to view your test run with.

You can register this debugger driver with a different name and set it
as the current javascript driver. By example, in your helper file:

Notice that headers= will overwrite already set headers. You should use
add_headers if you want to add a few more. These headers will apply to all
subsequent HTTP requests (including requests for assets, AJAX, etc). They will
be automatically cleared at the end of the test. You have ability to set headers
only for the initial request:

This way your temporary headers will be sent only for the initial request, all
subsequent request will only contain your permanent headers.

Inspecting network traffic

You can inspect the network traffic (i.e. what resources have been
loaded) on the current page by calling page.driver.network_traffic.
This returns an array of request objects. A request object has a
response_parts method containing data about the response chunks.
Please note that network traffic is not cleared when you visit new page.
You can manually clear the network traffic by calling page.driver.clear_network_traffic
or page.driver.reset

Manipulating cookies

The following methods are used to inspect and manipulate cookies:

page.driver.cookies - a hash of cookies accessible to the current
page. The keys are cookie names. The values are Cookie objects, with
the following methods: name, value, domain, path, secure?,
httponly?, expires.

page.driver.set_cookie(name, value, options = {}) - set a cookie.
The options hash can take the following keys: :domain, :path,
:secure, :httponly, :expires. :expires should be a Time
object.

:extensions (Array) - An array of JS files to be preloaded into
the phantomjs browser. Useful for faking unsupported APIs.

:port (Fixnum) - The port which should be used to communicate
with the PhantomJS process. Defaults to a random open port.

Troubleshooting

Unfortunately, the nature of full-stack testing is that things can and
do go wrong from time to time. This section aims to highlight a number
of common problems and provide ideas about how you can work around them.

DeadClient errors

Sometimes PhantomJS crashes during a test. There are basically two kinds
of crashes: those that can be reproduced every time, and those that
occur sporadically and are not easily reproduced.

If your crash happens every time, you should read the PhantomJS crash
reporting
guide and file
a bug against PhantomJS. Feel free to also file a bug against
Poltergeist in case there are workarounds that can be implemented within
Poltergeist. Also, if lots of Poltergeist users are experiencing the
same crash then fixing it will move up the priority list.

If your crash is sporadic, there is less that can be done. Often these
issues are very complicated and difficult to track down. It may be that
the crash has already been fixed in a newer version of WebKit that will
eventually find its way into PhantomJS. It's still worth reporting your
bug against PhantomJS, but it's probably not worth filing a bug against
Poltergeist as there's not much we can do.

If you experience sporadic crashes a lot, it may be worth configuring
your CI to automatically re-run failing tests before reporting a failed
build.

MouseEventFailed errors

When Poltergeist clicks on an element, rather than generating a DOM
click event, it actually generates a "proper" click. This is much closer
to what happens when a real user clicks on the page - but it means that
Poltergeist must scroll the page to where the element is, and work out
the correct co-ordinates to click. If the element is covered up by
another element, the click will fail (this is a good thing - because
your user won't be able to click a covered up element either).

Sometimes there can be issues with this behavior. If you have problems,
it's worth taking screenshots of the page and trying to work out what's
going on. If your click is failing, but you're not getting a
MouseEventFailed error, then you can turn on the :debug option and look
in the output to see what co-ordinates Poltergeist is using for the
click. You can then cross-reference this with a screenshot to see if
something is obviously wrong.

If you can't figure out what's going on and just want to work around the
problem so you can get on with life, consider using a DOM click
event. For example, if this code is failing:

click_button"Save"

Then try:

find_button("Save").trigger('click')

Timing problems

Sometimes tests pass and fail sporadically. This is often because there
is some problem synchronising events properly. It's often
straightforward to verify this by adding sleep statements into your
test to allow sufficient time for the page to settle.

Memory leak

If you run a few capybara sessions manually please make sure you've called
session.driver.quit when you don't need session anymore. Forgetting about this
causes memory leakage and your system's resources can be exhausted earlier than
you may expect.

General troubleshooting hints

Configure Poltergeist with :debug turned on so you can see its
communication with PhantomJS.

Take screenshots to figure out what the state of your page is when the
problem occurs.

Use the remote web inspector in case it provides any useful insight

Consider downloading the Poltergeist source and using console.log
debugging to figure out what's going on inside PhantomJS. (This will
require an understanding of the Poltergeist source code and PhantomJS,
so it's only for the committed!)

Filing a bug

If you can provide specific steps to reproduce your problem, or have
specific information that might help other help you track down the
problem, then please file a bug on Github.

Include as much information as possible. For example:

Specific steps to reproduce where possible (failing tests are even
better)

The output obtained from running Poltergeist with :debug turned on

Screenshots

Stack traces if there are any Ruby on Javascript exceptions generated

The Poltergeist and PhantomJS version numbers used

The operating system name and version used

Changes

Version history and a list of next-release features and fixes can be found in
the changelog.

License

Copyright (c) 2011-2014 Jonathan Leighton

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.